1. Field of the Invention
The present invention relates to electrical connectors used in automotive steering columns to provide electrical interconnection between rotative and stationary components thereof. More particularly, the present invention relates to an electrical connector of the aforesaid class which utilizes an electrically conductive liquid to provide electrical interconnection between mutually nontouching rotor and base terminals thereof.
2. Description of the Prior Art
Automotive vehicles have become increasingly sophisticated, both electronically and mechanically. One of the aspects of this sophistication is the introduction of air bag systems which are deployed in the event of a collision. For the driver, the logical choice location of the air bag is at the center hub of the steering wheel. However, in order for the air bag to be so located, the electrical systems associated with its actuation must accommodate the rotative movements of the steering wheel during driving of the vehicle. Other aspects of the aforementioned sophistication are steering wheel mounted controls for the horn, radio, cruise control and other electrically operated devices. These controls must also accommodate the rotative movements of the steering wheel. Accordingly, it has been industry practice to include an electrical connector within the steering column, wherein a first wiring connected with stationary components is connected with a second wiring connected with the rotative components on the steering wheel.
One conventional electrical connector in wide use is a clock spring electrical connector, sometimes referred to as a "coil". The clock spring electrical connector is of a cylindrical shape, having a base connected with the stationary components of the steering column, and a rotor which is rotatably connected with the base and connected with the rotative components of the steering column and/or the steering wheel. Internal to the base and rotor is a spirally wound, flat, multi-wire ribbon cable. The ribbon cable connects at one end to a first connection at the base, and connects at its other end to a second connection at the rotor. First wiring from the stationary portion of the vehicle connects with the first connection at the base. Second wiring from the steering wheel connects with the second connection at the rotor. Accordingly, electrical controls on the steering wheel are electrically connected to stationary parts of the vehicle, with rotative movements of the steering wheel being accommodated by the ribbon cable spiraling more or less tightly.
It is also possible to provide an electrical connector using a plurality of mutually electrically isolated slip rings, wherein respective brushes slidably contact therewith to thereby provide electrical contact between stationary and rotative components. One or the other of the slip rings and the brushes are mounted to a base and a rotor. The base is connected with the stationary components of the steering column and the rotor is rotatably connected with the base and connected with the rotative components of the steering column and/or the steering wheel.
The aforementioned conventional electrical connectors have a number of drawbacks. For example, the clock spring electrical connector utilizes a ribbon cable which is constantly undergoing movements which may tend to degrade the wires thereof at the first and second connections. Also, the clock spring coil is necessarily limited in how many rotations it can accommodate in any one direction; and because of the length of the ribbon cable, some resistive loss can be expected. Further for example, the slip ring and brushes type electrical connector involves considerable wear and the possibility of unreliable electrical contact.
Accordingly, what remains needed in the art is an electrical connector for a steering column which does not require either spirally wound wiring or slip rings and brushes to accommodate rotation of the steering wheel.